Multicolor diazotype layers



Patented Feb. 20, 1951 MULT'ICOLOR' DIAZOTYPE LAYERS Sam Charles Slifkin, Binghamton, N.'Y., assignor to General Aniline & Film Corporation, New York, N. Y., a corporation of Delaware No Drawing. Application D cember 5, 1947, se: rial No.- 790,025; In Great Britain July 16, 1945 11 Claims. (o1.- 95-6) r the reproduction media under a positive original is developed in the dry state by contact with a gaseous developing agent. This application is a continuation-in-part of my copending application Serial No. 545,201, filed July I5, 1944, now abandoned. I

Diazotypes of this class are generally produced by treating the surface of a suitable base such as paper, cellulose acetate film, cellophane, glass and metal surfaces with a solution of two dye components, one of which, the diazo compound, is the photosensitive body and the other, the azo component or coupling component, is a compound capable of reacting under suitable conditions with the diazo compound to form a dye. The diazo compound will decompose, upon ex-' posure to light, particularly light which emits rays in the 3600 A. to 4200 A. line, to form a com-' pound which can no longer combine. with the azo coupling component. This decomposition product, however, may itself be a coupling component and may be employed in some instances to combine with undecomposed diazo compound. When a diazotype layer containing a diazo compound and a coupling component is exposedunder an original tracing, design or printed sheet to a proper source of light, the diazo compound, in those areas which are not protected by the solid lines of the tracing or design or letters of the printed sheet, is decomposed, Upon subsequent development, a dye forms only in the areas which were protected from the light by the said lines of the tracing, design or letters of the printed sheet and thus the original is reproduced m the color called for by the particular combination of a maze compound and coupling component present in the light sensitive layer. In

cases where there is a distinct variation inthe' densities of various parts of the original which is to be copied, such as where there are ink lines and pencil marks or pencil lines on the same original drawing or where there are shadows and high-lights on a design, the lines of weaker density, half-tones or high-lights will appear, if at all, as indistinct or dispersed shades of the same color tone as the full densities or shadows. In many cases where the contrast be tween the full densities and the half-tones or high-lights of the original is very great, no' reproduction of the half-tones or high-lights will be obtained since the degree of exposure necessary to decompose the diazo compound in the background areas will also completely or almost completely decompose the diazo compound in the half-tone or high-light areas.

It has now been discovered that the full densi= ties or shadowsand' the half-tones or high-lights of an original can be reproduced in different colors, thus indicating the existing difference in densities without the necessity of creating such a low density in the reproduction of the halftones or high-lights as to render them indistinct. This effect is produced by adding to the light sensitive coating solution a number of coupling components differing widely from each other in their coupling rates or potentials and forming contrasting colors when coupled with the diazo compound.

It has been observed that the rate of formation of an azo'dye is dependent upon many variables-but is in large .part predetermined by the inherent nature of the-diazonium compound and the" coupler or couplers used in the formation of the azo dye. Thus, under identical conditions, a single d'iaz'ocompound will couple at greatly varying rates with a series of difierent azo components or couplers and a single coupling component will also couple at greatly varying rates with'a series of difierent diazo compounds. Thus, in the selection of' diazo compounds and couplers for the production of a diazotype light sensitive layer, the combination of a slow coupling diazo and a fast coupling azo component will be similar in effect to a fast coupling diazo and a a'given density area. The relative concentration of the coupling components-is also a contributin factor. Thus, concentration can be used to offset the unfair competition of the more energetic coupler having a higher coupling potential. Inareas where there is a high concentration of diazo thecoup'ler of high coupling potential will be used up first. Then coupling will take place with the less energetic coupler. By limiting the concentration of the high potential coupler the color produced by the slow coupler will predominate in such areas of high diazo concentration.

When using av continuous tone, or multi-density original the concentration of the light sensitive diaz'ois varied by exposure to light of a diazotype under such an original so that a series of different concentrations of diazo are produced on the irradiated sheet. The concentrawill become exhausted by the energetic coupler before the slow coupler has an opportunity to exert its influence. As the concentration of the diazo increases in the halftone areas, where there is not enough of the energetic coupler to combine with all of the residual diazo, more and more of the slow coupler will react until in the high density areas the slow coupler exerts its influence on the color produced to its fullest extent. Any color produced by the energetic or fast coupler in such areas will be completely overshadowed by the color of the slow coupler.

In order to obtain optimum contrast between the high density and low density areas it is preferable to not only react a combination of energetic and slow couplers which will produce contrasting colors with the diazo compound, but to combine the couplers in such a molar ratio to each other that the slow coupler will be in considerable excess. The exact ratio will depend upon the covering power of the color produced by the slow coupler, there being sufficient oi the more active or energetic coupler present to prevent any appreciable degree of coupling by the slow coupler in the half-tones or highlight areas. Ratios of from /10 to /4c in favor of the slow coupler have been found satisfactory.

Diazo compounds which are most suitable for the production of the dual tone or multicolor effects of this process are those which are derived from p-diamines of the benzene series. Examples of such diazo compounds are p-diazo-N-diethyl-m-toluidine; p-diazo-diphenylamine; pdiazo-N-diethylaniline; p-diaz-o-N-methylaniline; p-diazo-N-dimethylaniline; p-diazo-N-ethoxyaniline; p-diazo-N-ethyl-N-ethoxyaniline; 1- diazo-3-methyl-4-N-ethylaminobenzene; and 1- diazo 3 methoxy 4 N cyclohexylaminobenzene. used in the form of their double salt complexes, such as the zinc chloride double salt, the cadmium chloride double salt, the chlorobenzenesulfonate, the tin chloride doublesalt, the borofiuoride and the sulfate of the diazo compound.

This invention will be more fully understood from the following examples which are illustrative of the invention but are not intended to limit in any way the scope thereof. The parts are by weight unless otherwise specified.

Example I A coating solution is prepared by slowly mixing the following ingredients in the proportions given at room temperature Water "cc..- 80 Glycerin cc Citric acid g 10 Zinc chloride g 5 Thiourea g 5 2,3 dihydroxynaphthalene 6 sulfonic acid g 2.5 Acetoacetanilide g 0.07 p-Diazo-N-diethyl-m-toluidine lg .3

These diazo compounds are preferably A diazotype stock paper is coated with the above solution in the usual manner employing a doctor blade'to remove excess solution and the thus coated paper is then dried. Samples of this coated paper are then exposed to light under a diapositive having full density and half-tone areas and the thus exposed samples are then developed in the usual manner by contacting the sensitized side of the paper to a mixture of water vapor and ammonia gas. The full density areas of the diapositive original will be reproduced in a blue tone and the half-tone areas will be reproduced in a sepia tone.

Example II A coating solution is prepared by slowly mixing the following ingredients in the proportions given at room temperature:

Water cc 8O Glycerin cc 5 Citric acid g 10 Zinc chloride g 5 Thiourea 5 2,3 dihydroxynaphthalene 6 sulfonic acid g 2.5 Acetoacet-o-toluidide g 0.07 p-Diazo-N-diethyl-m-toluidine g 3 and .the half-tone areas are reproduced in a sepia tone.

Example III A coating solution is prepared by slowly mixing the following ingredients in the proportions given at room temperature:

Water cc 8O Glycerin cc 5 Citric acid 7 g 10 Zinc chloride g 5 Thiourea g 5 2,3-dihydroxynaphthalene-B-sulfonic acid g 2.5 o-Chloroacetoacetanilide g 0.07 p-Diazo-Ndiethyl-m-toluidine g 3 A diazotype stock paper is coated with the above solution in the usual manner employing a doctor blade to remove excess solution and the.

thus coated paper is then dried. Samples of this coated paper may then'be exposed to light under a diapositive having full density and half-tone areas and the thus exposed samples developed in'the usual manner by contacting the sensitized side of'the exposed paper to a mixture of water vapor and ammonia gas. The full densit areas of the original will be reproduced in a blue tone and the half-tone areas will be reproduced in an orange tona:

Example I V A coating solution is prepared by slowly mixing the following ingredients in' the proportions given at room temperature:

Water cc 80 Glycerin cc Citric acid g Zinc chlorideg 5 Thiourea g 5 2-amino-8-naphthol-3fi-disulfonic acid g 2.5 Acetoacetanilide-4-sulfonic acid g 0.25 p-Diazo-N-diethylaniline g 3 A diazotype stock paper is coated with the above solution in the usual manner employing a doctor blade to remove excess solution and the thus coated paper is then dried. Samples of this coated paper may then be exposed to light. under a diapositive having full density and half-tone areas and the thus exposed samples developed in the usual manner by contacting the sensitized side of the exposed paper to amixture of water vapor and ammonia gas. The full density areas of the original will be reproduced in a blue tone and the half-tone areas will be reproduced in a sepia tone.

Example V A coating solution is prepared b slowly mixing Y the following ingredients in the proportions given at room temperature:

Water c c- Glycerin cc 5 Citric acid g 10 Zinc chloride g 5 Thiourea g 5 '7 -hydroxynaphthalene-l-biguanide -g- 2.5 Acetoacetbenzylamidei-sulfonamide g 0.13 p-Diazo-diphenylamine g 3 A diazotype stock paper is coated with the above solution in the usual manner employing a doctor blade to remove excess solution and the thus coated paper is then dried. Samples of this coated paper may then be exposed to light under a diapositive original having full density and half-tone areas and the thus exposed samples developed in the usual manner by contacting the sensitized side of the exposed paper to a mixture of water vapor and ammonia gas. The full densiareas of the original will be reproduced in a purple tone and the half-tone areas will be reproduced in a sepia tone.

In the foregoing examples the acetoacetarylide is the fast coupler and the naphthol component is the slow coupler as indicated by their ratio of concentrations. Any acetoacetarylide coupler can be substituted in the respective examples for the specific acetoacetarylides, and any monoor dihydroxynaphthalene coupling component having a free coupling position may be substituted for the 2,3-dihydroxynaphthalene-6-sulfonic acid of Examples I to III, the 2-amino-8-naphthol- 3,6-disulfonic acid of Example IV, or the 7-hydroxynaphthalene-l-biguanide of Example V. Such monoand dihydroxynaphthalene couplers as the ethylenediamine amide of 2-hydroxy-3- naphthoic acid; the benzoyl derivative of 8-amino-1-naphthol-3,6-disulfonic acid; and and 2,8- dihydroxynaphthalene-o-sulfonic acid, all of which produce blue tones in the high density areas, are suitable for this latter substitution. As indicated above, the monoor dihydroxynaphthalene coupler should be in excess concentration over the acetoacetarylide coupler, which latter 6'; produces thei'contra'sting yellow tones in'the lbw density areas; The monc-- and dihydr-oxyna'phthalene' compounds having a free coupling position whichare employed as the slow couplers-may be represented by the following structural for mula:

wherein'nstands-for 1 or 2; 1?. stands for a whole number from 1; to. d; and R stands for amino, acylamino, guanyl-g-uanide, acyl, sulfonic acid groups,

1 or any other suitable substituent groups which do not introduce side chain coupling such asinthe case of: an acetoacetamido substitution or otherwiseprevent ring coupling. y Having. now'particularly set forth and described my" invention and having illustrated the best method of performing it, what I claim as new'is: 1. A diazotype light sensitive layer for there-- production of different photographic density areasofan original in contrasting colors which:

1 comprises in combination a light sensiti-vedia-zo compound of the class consisting of mono-diazoderivatives: of p-diamines of the benzene seriesand', in the ratioof approximately 1/10 to approximately l/35'by weight, afastcoupling-com ponentof the class consisting'of: acetocetyl aryl': amides, and a slow coupling component ofthe: class consisting of substituted monoand: dihy drox'ynaphthalene compounds having. a free con-- pling p'ositiom,

2. A diazotype light sensitive layer for the reproduction of different photographic density areas of an original in contrasting colors which comprises, in combination, a light sensitive diazocompound of the class consisting of mono-diazo derivatives of p-diamines of the benzene series; and, in the ratio of approximately 1/35 by weight, acetoacet-o-toluidide and 2,3-dihydroxynaphthalene-G-sulfonic acid.

3. A diazotype light sensitive layer for the reproduction of different photographic density areas of an original in contrasting colors which comprises in combination p-diazo-N-diethyl-mtoluidine and, in the ratio of approximately 1/35 by weight, acetoacet-o-touidide and 2,3-dihydroxynaphthalene-6-sulfonic acid.

4. A diazotype light sensitive layer for the reproduction of different photographic density areas of an original in contrasting colors which comprises, in combination, a light sensitive diazo compound of the class consisting of mono-diazo derivatives of p-diamines of the benzene series and, in the ratio of approximately 1/35 by weight, o-chloroaceto-acetanilide and 2,3 dihydroxynaphthalene-G-sulfonic acid.

5. A diazotype light sensitive layer for the reproduction of difierent photographic density areas of an original in contrasting colors which comprises in combination p-diazo-N-diethyl-mtoluidine and, in the ratio of approximately 1/35 by weight, o-chloroacetoacetanilide and 2,3-dihydroxynaphthalene-6-sulfonic acid.

6. A diazotype light sensitive layer for the reproduction of difierent photographic density areas of an original in contrasting colors which comprises, in combination, a light sensitive diazo compound of the class consisting of mono-diazo derivatives of p-diamines of the benzene series and, in the ratio of approximately 1/35 by weight, acetoacetanilide and 2,3-dihydroxynaphthalenefi-sulfonic acid.

7. A dia'z'otype light sensitive layer for the reproduction of different photographic density areas of an original in contrasting colors which comprises in combination p-diazo-N-diethyl-mtoluidine and, in the ratio of approximately 1/35 by weight, acetoacetanilide and 2,3-dihydro'xynaphthalene-G-sulfonic acid. l e

8. A diazotype light sensitive layer for the reproduction of different photographic density areas of an original in contrasting colors which comprises, in combination, a light sensitive diazo compound of the class consisting of mono-diazo derivatives of p-diamines in the benzene series and, in the ratio of approximately 1/10 by weight, aoetoacetanilide-4-sulfonic acid and 2-amino- 8-naphthol-3,6-disulfonic acid.

9. A diazotype light sensitive layer for the reproduction of difierent photographic density areas of an original in contrasting colors which comprises, in combination, p-diazo-N-diethyl aniline and, in the ratio of approximately 1/10 by weight, acetoacetanilide-4-sulfonic acid and 2-amino-8-naphtho1-3,6-disulfonic acid.

10. A diazotype light sensitive layer for the reproduction of different photographic density areas of an original in contrasting colors which comprises, in combination, a light sensitive diazo compound of the class consisting of mono-diazo derivatives of p-diamines of the benzene series and, in the ratio of approximately 1/20 by weight,

acetoacetbenzylamide-4-sulfonamide and 7-hyareas of an original in contrasting colors which comprises, in combination, p-diazodiphenylamine and, in the ratio of approximately 1/20 by weight, acetoacetbenzylamide-4-sulfonamide and 7-hydroxynaphthalene-l-biguanide.

SAM CHARLES SLIFKIN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,760,780 Schmidt et al May 27, 1930 1,845,989 Schmidt et al Feb. 16, 1932 1,966,755 DHauterine July 17, 1934 1,967,351 Schmidt et a1 July 24, 1934 1,989,065 Schmidt et a1. Jan. 22, 1935 2,034,508 De Boer et a1 Mar. 17, 1936 2,037,542 Schmidt et a1 Apr. 14, 1936 2,095,408 DeBoer et a1 Oct. 12, 1937 2,150,565 Schmidt et a1 Mar. 14, 1939 2,157,206 Hinman May 9, 1939 2,381,984 Reichal Aug. 14, 1945 FOREIGN PATENTS Number Country Date 660,087 France Feb. 12, 1939 OTHER REFERENCES Spencer: Photographic Application of Diazo Compounds, The Photographic Journal, London, Dec. 1928, pages 490 to 496. 

1. A DIAZOTYPE LIGHT SENSITIVE LAYER FOR THE REPRODUCTION OF DIFFERENT PHOTOGRAPHIC DENSITY AREAS OF AN ORIGINAL IN CONTRASTING COLORS WHICH COMPRISES IN COMBINATION A LIGHT SENSITIVE DIAZO COMPOUND OF THE CLASS CONSISTING OF MONO-DIAZO DERIVATIVES OF P-DIAMINES OF THE BENZENE SERIES AND, IN THE RATIO OF APPROXIMATELY 1/10 TO APPROXIMATELY 1/35 BY WEIGHT, A FAST COUPLING COMPONENT OF THE CLASS CONSISTING OF ACETOCETYL ARYL AMIDES, AND A SLOW COUPLING COMPONENT OF THE CLASS CONSITING OF SUBSTITUTED MONO- AND DIHYROXYNAPHTHALENE COMPOUNDS HAVING A FREE COUPLING POSITION. 